Coated pile fabric and method of making



COATED PILE FABRICSAND R/ETHOD OF MAKING Leo W. Rainard, Nyack, and Emory P. Mersereau, Jr.,

Thornwood, N. Y., assignors to Alexander Smith, Incorporated, White Plains, N. Y., a corporation of New York No Drawing. Application February 19, 1954, Serial No. 411,564

2 Claims. (Cl. 117-169) This invention relates to the treatment of surfaces to reduce the adherence or attraction of particles thereto and more particularly to the treatment of fabrics, paper and paper-like materials, paint films and other materials to reduce their color change due to pick-up and retention of particles on their exposed surfaces.

A more specific object is to reduce color change or greying of fabrics (fiat or pile), covering or wrapping material such as paper, and films such as paint or varnish, due to the pick-up and retention of particles during use.

Another object is to reduce the particle adherence of surfaces without introducing an undesirable discoloration or whitening or otherwise harmfully altering the appearance or feel of the treated material.

Another object is to reduce the adherence of soil particles to surfaces.

Other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

This application is a continuation-in-part of co-pending application Serial No. 213,304 filed February 28, 1951, and now abandoned.

In order to obtain comparative results and to determine the suitability of a selected composition for the above purpose a series of tests have been developed for measuring the particle adherence and the color change of a surface treated as described herein, called the adherence index and whitening index respectively. The adherence index is determined by comparing the color changes pro- .duced on treated and untreated samples, by the standardized soiling test procedure outlined below, using the same instrument for both tests. The whitening'index is the color change produced by the treating composition, as measured in a colorimeter. The adherence and whitening indices define the characteristics of the coating and are a measure of the nature of the composition which is applied to the material to form the coating. The composition used as a source of particles for measuring the adherence index is a synthetic soil composition which is described hereinafter. It is chosen because the treatments described herein have practical value in altering what are commonly termed the soil-resistance characteristics of fabrics or surfaces.

The standard test procedure is as follows:

ADHERENCE INDEX The adherence index test is made in a cylindrical ball mill, constructed of heavy gage metal 12" in diameter and 6" high. On the circumference are placed 3 equidistant openings 4"x 4". Three removable doors overlap these openings and are held to the mill by means of wing bolts. A 1" O. D. x 8" long steel perforated pipe is welded through the axis of the mill and contains a removable cap on one end and a sealed cap on the other. A perforated fiber tube is placed in this pipe and serves as the soil holder. Three radial steel baflies AV'xtS" are located on the inside wall of the mill, equidistant between the openings. Thirty steel balls 4" in size are placed in the mill.

nited States Patent O 2,734,834 Patented Feb. 14, 1956 In operation, samples of the material to be tested, such as a rug cut 5"x5 are placed over the openings in the mill so that /2" laps over on all sides. The removable doors are then clamped over the samples and the wing bolts tightened. A charge of synthetic soil particles is placed in the fiber tube and this in turn is placed in the steel pipe. The pipe is then capped and the mill rotated for 20 minutes at 60 R. P. M.

The synthetic soil is based on a composition set forth in an article in the Journal of Americal Oil Chemical Society, May 1950, pages 153-9, by H. L. Sanders and J. M. Lambert on a survey of the street dirt of six cities across the nation. A modification has been made to make it more applicable to this testing procedure. The

synthetic soil composition is as follows:

Composition: Percent Peat moss 37 Cement 17 Kaolin clay 17 Silica (200 mesh) l7 Molacco Furnace Black 1.75 Iron oxide .5 Mineral oil 8.75 v

The degree of pick-up of soil particles, or adherence index is calculated from measurements on a Color Eye (an electronic colorimeter made by the Instrument Development Labs). The instrument measures the tristimulus values X, Y and Z which give an indication of the redness, greenness and blueness respectively reflected from objects. Five places on each sample are measured before and after soiling in the ball mill using the Daylight illuminant. Specular reflectance setting, with a white vitrolite block as standard. For measuring a pile rug the sample is placed in the holder of the instrument and the average of five readings is computed for X, Y and Z. The adherence index is defined as the ratio of the color difference of the treated sample, before and after ball milling to the color difference of the untreated sample before and after ball milling, computed according to the following equation:

A I =Mm1aw where X'I', YT and Zr are the redness, greenness and WHITENING INDEX The whitening index is measured as the color difference between the treated sample and the untreated sample (prior to ball milling) measured on the Color Eye as above and computed according to the following equation:

Treatment which produces an adherence index of less than .85 and a whitening index of 10.6 or below, as determined by the above procedure, has been found satisfactory for improving the soil resistance of surfaces of the type specified.

The treatment in accordance with this invention comprises depositing on the surface to be protected a composition containing a metal oxide having characteristics which make it effective for the purpose as illustrated by the specific examples.

The oxide may be applied to the specimens from a dispersion under condition to leave a coating of oxide of the desired weight and composition after the vehicle has been removed. The coating may or may not be continuous.

The material can be treated in various ways depending upon its type and the results desired. In the case of pile fabrics, such as rugs or carpets, the dispersion may be sprayed over the pile surface in an amount to produce the desired particle pick-up, or the dispersion may be applied by means of a carpet cleaning brush, and then dried, or the fabric may be inverted and the pile only dipped into the dispersion. When used as a part of a standard rug-making process the dispersion may be sprayed onto the pile (face up) or the pile dipped (face down) after sizing and the treated rug then passed through a standard drier for removing the vehicle. If the treatment is applied to a carpet on the floor it may be dried at room temperature by allowing it to stand for a sufiicient period of time.

After drying the coating has the property of adhering strongly to the surface. If eventually removed as a result of repeated cleaning or use it can be easily renewed.

The treatment is effective on various textiles such as wool, cotton, jute, viscose rayon, acetate rayon, nylon, acrylics, polyesters, and other synthetic fibers and/or blends thereof.

Rugs having pile composed of wool yarn or a synthetic yarn or blends thereof, such as wool and rayon or wool and nylon may be treated by spraying the dispersion, preferably in the form of a fine mist and then drying.

Cotton pile rugs may be immersed in the dispersion until the desired pick-up has taken place on the fibers. The fabric is then passed between squeeze rollers and dried to leave the desired oxide coating on the pile.

The treatment is suited in general for any surface which is subject to particle adherence.

It has also been found that the treatment above described in many cases improves the resistance to moths and other insects and enhances the fire resistance of the treated materials.

The oxide should be hydrous, that is it may contain water of hydration or adsorbed or absorbed water in order to improve its adherence characteristics. It should also have a surface area in square meters per gram in the range of 15 to 200 with an average Working particle size of not over .6 micron, and an average primary or ultimate particle size of 5 to 50 millimicrons. A preferred range for best results is 35 to 130 square meters per gram. Certain oxides produced as set forth in the following examples have been found to have the characteristics required for the purpose of this invention.

Example 1 Pyrolytic alumina may be prepared as a reaction product resulting from the hydrolysis and dehydration of a volatile aluminum halide or from the thermal decomposition of aluminum sulfate in a high temperature gaseous environment. This finely divided product is an essentially crystalline form of aluminum oxide whose X-ray diffraction lines correspond most closely with those of the so-called gamma modification of alumina. The average primary particle size of the aluminum oxide may be produced over the range of 5-50 millimicrons diameter and a surface area range of l5-200 m. gram as measured by the Brunauer-Emmett-Teller method of low temperature nitrogen adsorption. The hydrous aluminum oxide produced by this process contains a minimum of 90% A1203, the remaining consisting of physically adsorbed moisture, chemically combined water (removable by heating to 1000 C.) and residual non-metallic elements resulting from the incomplete decomposition of the original aluminum-bearing raw material salts.

An example is a pyrolytic alumina sold under the trade name of Alon by Godfrey L. Cabot, Inc., which has a hardness of 9 (MHO scale) and a packed density of 4 to 5 pounds per cubic feet. It has an acid pH, is inert to the atmosphere, and to the materials treated.

A dispersion is prepared by agitating one part of Alon in parts of salt free water. This dispersion is sprayed as a fine mist onto the pile surface of an Axminster pile carpet having a backing composed of cotton chain and filler yarns, jute stuffer yarns and one-half inch pile having a weight of 23.2 ounces per square yard composed of a blend of 50% wool and 50% rayon. The pH of the pile was 4 to 4.5. The spray was controlled so that the weight of the dispersion taken up by the pile was about 100% of the pile weight and was concentrated on the pile with the backing remaining substantially dry. The carpet was then passed through a drier at a temperature of about F. to remove the water and leave a coating of hydrous alumina on the pile of about 1% by weight of the pile, corresponding to about .011 ounce per square yard of exposed fiber surface. The coating was most concentrated at the free ends of the pile although some of the coating may extend down to the portion of the pile anchored in the backing.

Samples of the carpet s0 treated, when given the adherence and whitening tests described above, were found to have an adherence index of .72 to .84 and a whitening index of 5.2 to 8.7. When applied as a coating of .75% by weight an adherence index of .80 and a Whitening index of 4.6 were obtained. A floor test in which the carpet was placed in a corridor adjacent an untreated sample where both samples were walked on equally by several thousand persons showed that this sample soiled more slowly than the same carpet untreated and Was more easily cleaned by a standard vacuum cleaner.

The dispersion may also be applied by inverting the carpet and dipping the pile only into the dispersion to obtain the same pick-up.

Oxides produced as above are herein defined as pyrolytic oxides.

Example 2 A dispersion in an organic vehicle may be made by adding one part Alon to 100 parts of isopropanol or of ethyl alcohol containing from 1% to 10% Water. This dispersion can be used as in the previous example.

Other volatile organic vehicles that can be used are:

Methanol Acetone Ethylene glycol Carbon tetrachloride The spraying or dipping may be controlled so that the desired weight of coating is formed.

A coating of 5% to 1.5% dry solids based on the weight of the pile has been found most effective for many types of pile materials although the coating may be varied from .25 to 5% for some purposes. An excess of the composition may be used but usually does not further decrease the adherence index and may increase the whitening index. ,In addition it may result in excessive dusting and may become noticeable in the feel of the material.

The surface area of fiber coated was calculated by the following equation:

Where W equals the totalv weight of fiber per square yard; As equals the effective exposed fiber surface area (in square yards) per square yard of fabric; D equals average density of the fiber in pounds per cubic yard calculated by (specific gravity) l685; d: equals average diameter of the fiber in yards calculated by (fiber diameter in microns) x 1.095 X 10*; and F equals a factor showing the average degree of penetration of the treating 1 s-WXEX XF dispersion expressed as a fraction of the total fiber area which is coated.

F values of from one-third to one-twelfth may be used, depending upon yarn construction, coating technique, fiber diameter, and fabric construction.

While in general the weight of coating varies from 0.25 per cent to 5.0 per cent of the fabric weight, the amount of material applied per square yard of exposed fiber surface may vary from .003 to .054 ounce per square yard of exposed fiber surface area computed as above. A range of .0063 to .024 ounce per square yard of exposed surface usually produces satisfactory results.

If pile surfaces are treated by spraying or dipping the major part of the coating is deposited on the exposed pile tufts toward the free ends thereof although some of the composition may migrate to the bound portions of the pile and to the backing.

Standard detergents, wetting and dispersing agents may be used with the above dispersions if desired. These are particularly useful to effect a combination of cleaning and treating.

What is claimed is:

1. A pile fabric having a backing and pile tufts anchored therein and extending upwardly therefrom, said pile tufts having a surface coating in an amount of .25% to by weight of the pile of a substance containing a major portion of a hydrous pyrolytic aluminum oxide having a surface area of 15 to 200 M /g., an average working particle size of not over .6 micron, said oxide being non-hygroscopic, inert to the atmosphere and inert to the material of the pile fabric, said coated surface having the adherence and whitening characteristics corresponding to an adherence index of not over .85 and a whitening index of not over 10.6 determined as defined herein.

2. The method of making a pile fabric having improved particle adherence characteristics and composed of a backing having pile tufts anchored therein and extending upwardly therefrom, which comprises applying to said pile tufts While in a substatially unsoiled condition a dilute dis persion composed of a liquid vehicle containing particles of pyrolytic aluminum oxide, said particles having a surface area of 15 to 200 M /g. and an average Working particle size of not over .6 micron, said oxide being nonhygroscopic, inert to the atmosphere and inert to said material, and removing the liquid vehicle to leave on said tufts a coating of said particles having a weight of .003 ounce to .054 ounce per square yard of exposed surface area to produce thereby a coated surface having adherence and whitening characteristics corresponding to an adherence index of not over .85 and a whitening index of not over 10.6 when determined as defined herein.

References Cited in the file of this patent UNITED STATES PATENTS 1,850,413 Porte Mar. 22, 1932 1,947,597 Hoelkeskamp Feb. 20, 1934 1,980,428 Parkinson Nov. 13, 1934 1,983,349 Dreyfus Dec. 4, 1934 2,085,129 Stoewener June 29, 1937 2,093,454 Kisfler Sept. 21, 1937 2,266,636 Hauser Dec. 16, 1941 2,570,750 Bauer Oct. 9, 1951 2,587,505 Moody Feb .26, 1952 2,622,307 Cogovan et a1 Dec. 23, 1952 

1. A PILE FABRIC HAVING A BACKING AND PILE TUFTS ANCHORED THEREIN AND EXTENDING UPWARDLY THEREFROM, SAID PILE TUFTS HAVING A SURFACE COATING IN AN AMOUNT OF .25% TO 5% BY WEIGHT OF THE PILE OF A SUBSTANCE CONTAINING A MAJOR PORTION OF A HYDROUS PYROLYTIC ALUMINUM OXIDE HAVING A SURFACE AREA OF 15 TO 200 M2/G., AN AVERAGE WORKING PARTICLE SIZE OF NOT OVER .6 MICRON, SAID OXIDE BEING NON-HYGROSCOPIC, INERT TO THE ATMOSPHERE AND INERT TO THE MATERIAL OF THE PILE FABRIC, SAID COATED SURFACE HAVING THE ADHERENCE AND WHITENING CHARACTERISTICS CORRESPONDING TO AN ADHERENCE INDEX OF NOT OVER .85 AND A WHITENING INDEX OF NOT OVER 10.6 DETERMINED AS DEFINED HEREIN. 